1. Field of the Invention
The present invention relates in general to de-duplicated data and methods of transferring de-duplicated data that is organized in virtual volumes to a target set of physical media.
2. Description of the Related Art
Data deduplication is a data storage method for eliminating or reducing redundant data. In particular, data deduplication allows one unique instance of the data to be retained on storage media rather than multiple instances of the same data by replacing the multiple instances of the same data with a pointer to a single instance. In this regard, data stored into a deduplication system is analyzed and broken into “blocks.” Duplicate blocks are identified, each unique block is given a digital signature to show that the two blocks with the same signature are the same data, and the duplicate blocks are eliminated. Normally, as the deduplication system breaks apart data comprising larger objects into the individual blocks, the system tracks the individual blocks so that the corresponding larger object can be retrieved when desired. For example, an index or database is provided to track the blocks.
The deduplication system may be embodied in a storage management system that spans multiple storage volumes and storage pools. For example, data may be sent by storage management clients or data protection agents to the storage management server for storage. In this regard, a storage management system typically stores copies of objects on separate media, so that a data set that is too large to fit on a single volume can be stored. Alternatively, data can be moved from one storage location to another, either within the same storage pool or between storage pools or between different media, such as between a disk and tape, which store different amounts of data.